fwt2_po.sci

小波分解源代码

function wc = FWT2_PO(x,L,qmf)
// FWT2_PO -- 2-d MRA wavelet transform (periodized, orthogonal)
//  Usage
//    wc = FWT2_PO(x,L,qmf)
//  Inputs
//    x     2-d image (n by n array, n dyadic)
//    L     coarse level
//    qmf   quadrature mirror filter
//  Outputs
//    wc    2-d wavelet transform
//
//  Description
//    A two-dimensional Wavelet Transform is computed for the
//    array x.  To reconstruct, use IWT2_PO.
//
//  See Also
//    IWT2_PO, MakeONFilter
//
//  Copyright Aldo I Maalouf

	[n,J] = quadlength(x);
	wc = x; 
	nc = n;
	for jscal=J-1:-1:L,
		top = (nc/2+1):nc; bot = 1:(nc/2);
		for ix=1:nc,
			row = waverow(wc(ix,1:nc));
			wc(ix,bot) = DownDyadLo(row,qmf);
			wc(ix,top) = DownDyadHi(row,qmf);
		end
		for iy=1:nc,
			row = waverow(wc(1:nc,iy))';
			wc(top,iy) = DownDyadHi(row,qmf)';
			wc(bot,iy) = DownDyadLo(row,qmf)'; 
		 end
		nc = nc/2;
	end   
	endfunction